# Antibiotic-sparing strategies targeting outer membrane ushers in Gram-negative bacterial pathogens

> **NIH NIH U19** · WASHINGTON UNIVERSITY · 2021 · $368,966

## Abstract

PROJECT SUMMARY/ ABSTRACT:
The rise of antibacterial resistance highlights the urgent need to develop new effective strategies to combat
antibiotic-resistant infections. Ubiquitously, Gram-negative bacterial pathogens assemble extracellular fibers,
termed chaperone-usher pathway (CUP) pili, that are critical for the pathogen's ability to cause infections by
recognizing and colonizing different host tissues and habitats. Thus, therapeutics targeting the assembly of
these fibers hold promise in their potential to result in much needed alternatives for the treatment of multidrug-
resistant Gram-negative pathogens. Among these pathogens are those designated as “Urgent Threats”
carbapenem-resistant Acinetobacter and carbapenem-resistant Enterobacteriaceae (CRE), as well as “Serious
Threats” drug-resistant Campylobacter, extended-spectrum beta-lactamase (ESBL)-producing
Enterobacteriaceae, multidrug-resistant Pseudomonas aeruginosa, drug-resistant Salmonella, Shigella, and
Bordetella pertussis. In each CUP pilus system, a designated periplasmic chaperone and an outer-membrane
(OM) usher protein work together to assemble thousands of structural subunits into each final pilus structure.
Most CUP pili are also tipped by adhesins that specifically recognize receptors in host tissues. We have made
considerable progress towards understanding the remarkably complex mechanisms of pilus assembly. Building
on our extensive experience and expertise in CUP pilus biogenesis and in the development of rational
therapies targeting CUP pili, this proposal seeks to develop novel antibiotic-sparing therapies targeting the OM
ushers using multidisciplinary approaches including bacteriology, chemical biology, medicinal chemistry,
structural biology and immunology. Based on the structural characterizations and the dynamic nature of these
multi-domain usher proteins, we will rationally develop small molecule usher inhibitors and pore openers by
trapping specific conformational states (Aim 1). Usher inhibitors will disarm bacterial virulence factors, whereas
pore openers will increase permeability of existing antibiotics into bacterial outer membranes. In addition, we
will develop monoclonal antibodies that inactivate usher, thus preventing pilus biogenesis and infection (Aim
2). While our first two aims will concentrate on two of the most studied pilus systems (type 1 and P pili), Aim 3
will expand our studies of ushers in Acinetobacter, Campylobacter, P. aeruginosa, Salmonella, Shigella, and B.
pertussis. Collectively, we plan to develop rational therapies against multiple antibiotic-resistant Gram-negative
bacterial pathogens. These developments, together with other novel strategies proposed in our
multidisciplinary U19 program, will work synergistically to act as efficient antibiotic-sparing therapeutics by
blocking usher and adhesin functions. Moreover, the usher pore openers developed in this proposal will
increase OM permeability, further alleviating antibiotic resista...

## Key facts

- **NIH application ID:** 10162828
- **Project number:** 1U19AI157797-01
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** Peng Yuan
- **Activity code:** U19 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $368,966
- **Award type:** 1
- **Project period:** 2021-03-01 → 2026-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10162828

## Citation

> US National Institutes of Health, RePORTER application 10162828, Antibiotic-sparing strategies targeting outer membrane ushers in Gram-negative bacterial pathogens (1U19AI157797-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10162828. Licensed CC0.

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